Unless otherwise indicated herein, the materials described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.
Glucose oxidase (GOx) is an oxido-reductase that catalyzes the oxidation of glucose to hydrogen peroxide and D-glucono-δ-lactone. Due to this property, GOx has been widely used to make biosensors to measure glucose for both in vitro and in vivo applications. For in vivo biosensors, the enzyme is typically immobilized onto the sensors. Immobilization can be accomplished by physically trapping the GOx in the biosensor or by chemically crosslinking the GOx in the biosensor.
Physically trapping the GOx in the sensor can be accomplished by initiating polymerization of a mixture including one or more polymerizable monomers and GOx. But this method suffers from the low solubility of GOx in the formulation and by the slow leaching out of the GOx from the resulting polymer matrix. Chemical crosslinking can be accomplished by reacting glutaraldehyde with the free amine groups on GOx. But glutaraldehyde-bound GOx sensors are hindered by the toxicity of glutaraldehyde and a loss of enzymatic activity of the GOx.